tcs.c

test file nucleus source

/* CALLS                                                                 */
/*                                                                       */
/*      [HIC_Make_History_Entry]            Make entry in history log    */
/*      TCC_Signal_Shell                    Signal execution shell       */
/*      [TCT_Check_Stack]                   Stack checking function      */
/*      TCT_Protect                         Protect against other access */
/*      TCT_Unprotect                       Release protection           */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      signal_handler                      Signal execution shell       */
/*                                                                       */
/* OUTPUTS                                                               */
/*                                                                       */
/*      NU_SUCCESS                                                       */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*         DATE                    REMARKS                               */
/*                                                                       */
/*      03-01-1993      Created initial version 1.0                      */
/*      04-19-1993      Verified version 1.0                             */
/*      05-15-1993      Corrected problem with a comment                 */
/*      05-15-1993      Verified comment repair                          */
/*      03-01-1994      Added register optimizations,                    */
/*                      modified protection logic,                       */
/*                      resulting in version 1.1                         */
/*                                                                       */
/*      03-18-1994      Verified version 1.1                             */
/*                                                                       */
/*************************************************************************/
STATUS  TCS_Register_Signal_Handler(VOID (*signal_handler)(UNSIGNED))
{

R1 TC_TCB      *task;                       /* Task pointer              */
NU_SUPERV_USER_VARIABLES

    /* Switch to supervisor mode */
    NU_SUPERVISOR_MODE();

#ifdef  NU_ENABLE_STACK_CHECK

    /* Call stack checking function to check for an overflow condition.  */
    TCT_Check_Stack();

#endif

#ifdef  NU_ENABLE_HISTORY

    /* Make an entry that corresponds to this function in the system history
       log.  */
    HIC_Make_History_Entry(NU_REGISTER_SIGNAL_HANDLER_ID,
                        (UNSIGNED) signal_handler, (UNSIGNED) 0, (UNSIGNED) 0);

#endif

    /* Pickup the task pointer.  */
    task =  (TC_TCB *) TCD_Current_Thread;

    /* Protect against simultaneous access.  */
    TCT_Protect(&TCD_System_Protect);

    /* Put the new signal handler in.  */
    task -> tc_signal_handler =  signal_handler;

    /* Now, determine if the signal handler needs to be invoked.  */
    if ((task -> tc_enabled_signals & task -> tc_signals) &&
        (!task -> tc_signal_active) &&
        (task -> tc_signal_handler))
    {

        /* Signal processing is required.  */

        /* Indicate that signal processing is in progress.  */
        task -> tc_signal_active =  NU_TRUE;

        /* Clear the saved stack pointer to indicate that this is an
           in line signal handler call.  */
        task -> tc_saved_stack_ptr =  NU_NULL;

        /* Release protection from multiple access.  */
        TCT_Unprotect();

        /* Call the signal handling shell. */
        TCC_Signal_Shell();
    }
    else

        /* Release protection.  */
        TCT_Unprotect();

    /* Return to user mode */
    NU_USER_MODE();

    /* Return success.  */
    return(NU_SUCCESS);
}


/*************************************************************************/
/*                                                                       */
/* FUNCTION                                                              */
/*                                                                       */
/*      TCS_Send_Signals                                                 */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This function sends the specified task the specified signals.    */
/*      If enabled, the specified task is setup in order to process the  */
/*      signals.                                                         */
/*                                                                       */
/* CALLED BY                                                             */
/*                                                                       */
/*      Application                                                      */
/*      TCSE_Send_Signals                   Error checking shell         */
/*                                                                       */
/* CALLS                                                                 */
/*                                                                       */
/*      [HIC_Make_History_Entry]            Make entry in history log    */
/*      TCC_Resume_Task                     Resume task that is suspended*/
/*      TCC_Signal_Shell                    Signal execution shell       */
/*      TCT_Build_Signal_Frame              Build a signal frame         */
/*      [TCT_Check_Stack]                   Stack checking function      */
/*      TCT_Control_To_System               Control to system            */
/*      TCT_Protect                         Protect against other access */
/*      TCT_Unprotect                       Release protection           */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      task_ptr                            Task pointer                 */
/*      signals                             Signals to send to the task  */
/*                                                                       */
/* OUTPUTS                                                               */
/*                                                                       */
/*      NU_SUCCESS                                                       */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*         DATE                    REMARKS                               */
/*                                                                       */
/*      03-01-1993      Created initial version 1.0                      */
/*      04-19-1993      Verified version 1.0                             */
/*      03-01-1994      Modified function interface,                     */
/*                      added register optimizations,                    */
/*                      modified protection logic,                       */
/*                      resulting in version 1.1                         */
/*                                                                       */
/*      03-18-1994      Verified version 1.1                             */
/*      04-04-1996      On line 995, changed tc_signals                  */
/*                      to tc_enabled_signals,                           */
/*                      resulting in version 1.1+                        */
/*                      (spr 107)                                        */
/*                                                                       */
/*************************************************************************/
STATUS  TCS_Send_Signals(NU_TASK *task_ptr, UNSIGNED signals)
{

R1 TC_TCB      *task;                       /* Task control block ptr    */
NU_SUPERV_USER_VARIABLES

    /* Switch to supervisor mode */
    NU_SUPERVISOR_MODE();

    /* Move input task control block pointer into internal pointer.  */
    task =  (TC_TCB *) task_ptr;


#ifdef  NU_ENABLE_STACK_CHECK

    /* Call stack checking function to check for an overflow condition.  */
    TCT_Check_Stack();

#endif

#ifdef  NU_ENABLE_HISTORY

    /* Make an entry that corresponds to this function in the system history
       log.  */
    HIC_Make_History_Entry(NU_SEND_SIGNALS_ID, (UNSIGNED) signals,
                                        (UNSIGNED) 0, (UNSIGNED) 0);

#endif

    /* Protect against simultaneous access.  */
    TCT_Protect(&TCD_System_Protect);

    /* Or the new signals into the current signals.  */
    task -> tc_signals =  task -> tc_signals | signals;

#ifdef INCLUDE_PROVIEW
    _RTProf_DumpTask(task,RT_PROF_SEND_SIGNALS);
#endif
    /* Now, determine if the signal handler needs to be invoked.  */
    if ((task -> tc_signals & task -> tc_enabled_signals) &&
        (!task -> tc_signal_active) &&
        (task -> tc_status != NU_TERMINATED) &&
        (task -> tc_status != NU_FINISHED) &&
        (task -> tc_signal_handler))
    {

        /* Indicate that signal processing is in progress.  */
        task -> tc_signal_active =  NU_TRUE;

        /* Signal processing is required.  Determine if the task is sending
           signals to itself or if the calling thread is not the current
           task.  */
        if (task == (TC_TCB *) TCD_Current_Thread)
        {

            /* Task sending signals to itself.  */

            /* Clear the saved stack pointer to indicate that this is an
               in line signal handler call.  */
            task -> tc_saved_stack_ptr =  NU_NULL;

            /* Release protection from multiple access.  */
            TCT_Unprotect();

            /* Call the signal handling shell. */
            TCC_Signal_Shell();
        }
        else
        {

            /* Target task must be prepared to receive the signals.  */

            /* First, insure that the target task is not in a protected
               area.  */
            do
            {

                /* Check for protection.  Remember that protection is still
                   in effect.  */
                if (task -> tc_current_protect)
                {

                    /* Yes, target task is in a protected mode.  Release
                       the protection on the scheduling list and transfer
                       control briefly to the target task.  */
                    TCT_Unprotect();

                    /* Switch to the protected task and wait until the
                       task is not protected.  */
                    TCT_Protect_Switch(task);

                    /* Restore protection on the scheduling structures.  */
                    TCT_Protect(&TCD_System_Protect);
                }
            } while (task -> tc_current_protect);

            /* Copy the current status and stack pointer to the signal save
               areas.  */
            task -> tc_saved_status =           task -> tc_status;
            task -> tc_saved_stack_ptr =        task -> tc_stack_pointer;

            /* Build a stack frame for the signal handling shell function. */
            TCT_Build_Signal_Frame(task);

            /* Determine if the target task is currently suspended.  If it is
               suspended for any other reason than a pure suspend, resume
               it.  */
            if ((task -> tc_status != NU_READY) &&
                (task -> tc_status != NU_PURE_SUSPEND))
            {

                /* Resume the target task and check for preemption.  */
                if (TCC_Resume_Task(task_ptr, task -> tc_status))

                    /* Preemption needs to take place.  */
                    TCT_Control_To_System();
            }
        }
    }

    /* Release protection, no signals are currently enabled.  */
    TCT_Unprotect();

    /* Return to user mode */
    NU_USER_MODE();

    /* Return a successful status.  */
    return(NU_SUCCESS);
}